Endoscope tip attachment device

ABSTRACT

Embodiments of the disclosure include an endoscope tip assembly for use on an endoscope, during procedures. The endoscope tip assembly may include a base configured to receive an endoscope tip configured to not disengage from the endoscope tip during a procedure. The endoscope tip assembly may also include a plurality of struts which is connected by a webbing, may fold flat during insertion, and may assume a balloon-like shape during withdrawal.

TECHNICAL FIELD

Embodiments of the present disclosure relate to an endoscope accessoryand more particularly, to an endoscope tip assembly for supporting thedistal tip of an endoscope and/or for improving the field of view of anendoscope during use.

BACKGROUND ART

In endoscopic procedures, endoscopes are inserted through an orifice orincision into a body lumen. The endoscopes may be guided throughinternal body lumens, e.g., the gastrointestinal tract, to a region ofinterest, such as the stomach, cecum, duodenum, small intestine, largeintestine, or esophagus. The instruments are provided with afiber-optic, charge-coupled device (CCD), or complementarymetal-oxide-semiconductor (CMOS) camera, which enable images to betransmitted along the endoscopes having flexibility and reproduced on adisplay external to the body of the patient. Accordingly, it is possibleto view the internal surfaces of the body lumens during theseprocedures. For example, a gastroscope may be used to view the internalsurfaces of the esophagus, stomach, or duodenum.

The endoscopic procedures may be used to provide visual diagnosis (e.g.,of an ulceration or polyp), treatment, biopsy, and/or removal of tissue.While colonoscopic and enteroscopic examinations may be effectivetechniques to assess the state of health of an internal body region,they may cause complications and, in some instances may fail to allow aclinician to accurately visualize a region of interest.

For example, the clinician may not be able to complete a procedure mayfail to detect a polyp, lesion, or other tissue, or may cause injury toa body lumen in which the endoscope is inserted, e.g., via theapplication of a traumatic force, which may result in inflammation,burns, bleeding, scarring, perforation, or other injury.

Endoscopic procedures may be time consuming for patients and medicalpersonnel alike, depending upon how difficult it is to advance a scopethrough the body lumen or to view the surrounding region of the bodylumen. Increased procedure time requires a patient to be sedated forlonger periods may increase patient discomfort, and thus may increaserecovery time. Additionally, there is an in-hospital recovery period,which may last several hours while the anesthesia wears off, and, duringthat time, clinical observation is needed. Increased procedure timefurther cuts down on the number of procedures that a given team ofclinicians can perform in one day and limits the use of an operatingroom.

Anatomical and technological limitations may also contribute to thedifficulties of these procedures. First, the anatomy of a body lumen,e.g., the colon may be tortuous, and the lining thereof may be uneven.For example, the colon includes a series of folds. As the tip of theendoscope passes along the lumen of the colon, these folds may hamperthe clinician's ability to visualize the entire surface of the mucosaand, in particular, to detect pre-malignant and malignant lesions andpolyps located along these folds. For example, during endoscopewithdrawal, lesions located on the distal faces of these folds may notbe visualized.

Second, the tip position of the endoscope may be difficult to maintainonce a lesion or polyp is detected and/or during a therapeutic,diagnostic, or biopsy procedure. Due to gravity, the endoscope tip maynot stay centered within the colon and may instead fall against the wallof the colon. As a colonoscope is inserted or withdrawn, the tip mayslide and drop inconsistently along the colon as it moves over thefolds. This movement and/or the effect of gravity may cause theclinician to become disoriented, lose visualization, or losepositioning. If the tip position is lost, time must be taken to againrelocate the region of interest.

Additionally, the tortuous nature of the gastrointestinal tract may makeit difficult for the clinician to navigate the endoscope to the regionof interest. The turns of the bowel, folded surface of the colon, andeffects of gravity may cause the endoscope to bump and press on the bodylumen as the endoscope is advanced or withdrawn. This may lead tostretching of the bowel, perforation, bleeding, trauma to the mucosa,inflammation, or other injury. As a result, the patient may experiencepain, the patient's recovery time may increase, procedure time mayincrease, or the procedure may even need to be aborted prematurely.

A number of products have attempted to address the challenges associatedwith endoscopic procedures. For example, active balloon endoscopes andballoon attachments have been developed. The balloon expands wheninserted into the colon to aid in retrieval and visualization. However,these devices may be complex to manufacture and use due to the need forinflation and deflation mechanisms and the delicateness of the expandingportions. Additionally, active balloons that form a permanent part of anendoscope make scope-reprocessing (e.g., high level cleaning anddisinfection) more difficult.

Other distal endoscope attachments that have rows of protrusions havebeen developed to aid in opening up colonic folds. However, theprotrusions of those devices typically provide very similar stiffnessand resistance to force in the direction of insertion and the directionof withdrawal.

However, when inserting an endoscope, it is desirable to have reducedresistance on the distal tip. Since insertion involves two motions,linear advance and torqueing, the resistance to both of those motionsshould be low. Upon withdrawal, a device should engage with the colon toopen the folds. This means that protrusions should be compliant and havelow flexing and torqueing stiffness upon insertion, and should beconfigured to interact and engage with the colon and have relativelyhigher flexing stiffness upon withdrawal.

If the protrusions are stiff upon insertion, this may cause increasedinsertion resistance, which then might cause the scope to loop andstretch the colon walls. This might produce mucosal trauma as theendoscope is inserted or withdrawn. Additionally, force applied by thetips of the protrusions to discrete surface areas of the wall of thebody lumen may increase mucosal trauma or cause perforation. On theother hand, if the protrusions are not stiff on withdrawal, they may notbe capable of opening the colonic folds and may not help withvisualization of the regions adjacent to the folds, as intended.

CITATION LIST Patent Literature

Patent Literature 1: JP 2003-180611 A

Patent Literature 2: JP 2016-507303 W

Patent Literature 3: JP 2013-529958 W

SUMMARY OF INVENTION Technical Problem

Accordingly, an improved endoscope attachment device is needed that ismore compliant upon insertion and has a higher resistance to force uponwithdrawal. Such a device may be capable of safely and effectivelyreducing the time taken for the clinician to perform an endoscopicprocedure and for increasing the effectiveness of the procedure.

The device of the present disclosure aims to overcome the limitations ofthe prior art by facilitating one or more of the following: Lowresistance in an insertion direction; more effective opening of folds onwithdrawal, steadying and/or centering the endoscope tip's positionduring a medical procedure; reducing the potential for mucosal trauma;and/or providing better physical and/or visual access around colonicfolds.

Solution to Problem

Embodiments of the present disclosure relate to an endoscope tipassembly. Various embodiments of the disclosure may include one or moreof the following aspects.

In accordance with one embodiment, an endoscope tip assembly mayinclude: a ring-shaped base having a substantially cylindrical innersurface that is dimensioned to receive a distal end of an endoscope; anda collapsible umbrella extending radially out from the base, where thecollapsible portion includes: a plurality of struts collapsiblyradiating away from the base; and a webbing connecting two adjacentstruts of the plurality of struts, where the struts are flexible strutsconfigured to flex to transition the collapsible umbrella between aninsertion state and a withdrawal state; where the flexible struts areeach attached to the inner surface of the base and extend from the innersurface, around an edge of the base, and radiate away from an outersurface of the base; and where, in the insertion state, the plurality ofstruts are flexed toward a direction extending substantially parallelwith the outer surface of the base, and where, in the withdrawal state,the plurality of struts are flexed outward away from the outer surfaceof the base, and the tip of each of the plurality of struts points in adistal direction substantially parallel to the outer surface of thebase. Each of the plurality of struts may have a recessed portionreceiving the base.

Various embodiments of the endoscope tip assembly may include: a tipassembly where a force required to flex the plurality of struts totransition the collapsible portion to the insertion state is less than aforce required to flex the plurality of struts to transition thecollapsible portion to the withdrawal state; a tip of each of theplurality of struts being off-axis from an intermediate portion of eachof the plurality of struts; at least one of the plurality of strutsincluding one or more notches located along a distal-facing surface ofthe strut; and a base being substantially rigid.

Various embodiments of the endoscope tip assembly may include: an innersurface of a base including at least one crush rib projecting from theinner surface; webbing being pleated; an outer surface of the baseincluding at least one gripping structure; and an outer surface of thebase including at least one self-locking window.

Various embodiments of the endoscope tip assembly may include: a baseincluding a shaft sleeve, a sleeve lock, and a strut support ring; and abase including a distal cap and a shaft sleeve.

Additional objects and advantages of the embodiments will be set forthin part in the following description, and in part will be obvious fromthe description or may be understood from practice of the embodiments.The objects and advantages of the embodiments will be realized andattained by means of the elements and combinations particularly pointedout in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the claims.

The accompanying drawings, which are incorporated in and constitute apart of this description, illustrate the disclosed embodiments and,together with the description, serve to explain the principles of thedisclosed embodiments.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an exemplary endoscope tip assembly, with pleatedwebbing, according to an embodiment of the present disclosure.

FIG. 2 illustrates an exemplary endoscope tip assembly, according to anembodiment of the disclosure.

FIG. 3 illustrates an exemplary endoscope tip assembly, with the webbingremoved for clarity, according to an embodiment of the disclosure.

FIG. 4 illustrates an exemplary endoscope tip assembly, with the webbingremoved for clarity, according to an embodiment of the disclosure.

FIG. 5 illustrates an exemplary endoscope for receiving an endoscope tipassembly.

FIG. 6 illustrates an exemplary endoscope tip assembly mounted on anendoscope in a resting position, according to an embodiment of thedisclosure.

FIG. 7A illustrates an exemplary endoscope tip assembly mounted on anendoscope in an insertion position, according to an embodiment of thedisclosure.

FIG. 7B illustrates an exemplary endoscope tip assembly mounted on anendoscope in a withdrawal state, according to an embodiment of thedisclosure.

FIG. 8 illustrates an exemplary endoscope tip assembly mounted on anendoscope in a withdrawal position, according to an embodiment of thedisclosure.

FIG. 9A illustrates an exemplary endoscope tip assembly mounted on anendoscope in a withdrawal position inside of a colon, according to anembodiment of the disclosure.

FIG. 9B illustrates an endoscope, equipped with a balloon, inside of acolon.

FIG. 10 illustrates an exemplary endoscope tip assembly with struts inan insertion position and the webbing removed for clarity, according toan embodiment of the disclosure.

FIG. 11 illustrates an exemplary endoscope tip assembly with strutsextended past the withdrawal position, and the webbing removed forclarity, according to an embodiment of the disclosure.

FIG. 12 illustrates a magnified view of a portion of an exemplaryendoscope tip assembly with struts in a resting position, and thewebbing removed for clarity, according to an embodiment of thedisclosure.

FIG. 13 illustrates an exemplary endoscope tip assembly in a restingposition, with the webbing removed for clarity, according to anembodiment of the disclosure.

FIG. 14 illustrates an exemplary strut for an endoscope tip assembly,according to an embodiment of the disclosure.

FIG. 15 illustrates an exemplary strut for an endoscope tip assembly,according to an embodiment of the disclosure.

FIG. 16 illustrates an exemplary endoscope tip assembly, with thewebbing removed for clarity, according to an embodiment of thedisclosure.

FIG. 17A illustrates an exemplary endoscope tip assembly mounted on anendoscope in a resting position, according to an embodiment of thedisclosure.

FIG. 17B illustrates an angled view of a part of an exemplary endoscopetip assembly mounted on an endoscope in a resting position, according toan embodiment of the disclosure.

FIG. 18A illustrates an exemplary endoscope tip assembly mounted on anendoscope in a resting position, according to an embodiment of thedisclosure.

FIG. 18B illustrates an angled view of a part of an exemplary endoscopetip assembly mounted on an endoscope in a resting position, according toan embodiment of the disclosure.

FIG. 19A illustrates an exemplary endoscope tip assembly in a restingposition, according to an embodiment of the disclosure.

FIG. 19B illustrates an exemplary endoscope tip assembly mounted on anendoscope in a resting position, according to an embodiment of thedisclosure.

FIG. 20A illustrates an exemplary endoscope tip assembly in a restingposition, according to an embodiment of the disclosure.

FIG. 20B illustrates an exemplary endoscope tip assembly in a restingposition, according to an embodiment of the disclosure.

FIG. 21A illustrates a cross-section view of a strut in an insertionposition, according to an embodiment of the disclosure.

FIG. 21B illustrates a cross-section view of a strut in a restingposition, according to an embodiment of the disclosure.

FIG. 21C illustrates a cross-section view of a strut in a withdrawalposition, according to an embodiment of the disclosure.

FIG. 22 illustrates an exemplary endoscope tip assembly, with pleatedwebbing that does not extend to the end of the strut, according to anembodiment of the present disclosure.

FIG. 23 illustrates an exemplary endoscope tip assembly, with pleatedwebbing that does not extend to the end of the strut, according to anembodiment of the present disclosure.

FIG. 24 illustrates an exemplary endoscope tip assembly mounted on anendoscope in a resting position, according to an embodiment of thedisclosure.

FIG. 25A illustrates an exemplary endoscope tip assembly mounted on anendoscope in a resting position, according to an embodiment of thedisclosure.

FIG. 25B illustrates an exemplary endoscope tip assembly mounted on anendoscope in a resting position, according to an embodiment of thedisclosure.

FIG. 26A illustrates an enlarged view of a portion of an inner surfaceof an endoscope tip assembly.

FIG. 26B illustrates an enlarged view of a portion of an inner surfaceof an endoscope tip assembly.

FIG. 26C illustrates an enlarged view of a portion of an inner surfaceof an endoscope tip assembly.

FIG. 27 is a graph illustrating a relationship of a change in resistanceforce to the angle of a strut.

FIG. 28A illustrates a condition under which there is no slack in awebbing.

FIG. 28B illustrates a condition under which there is no slack in awebbing.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the exemplary embodiments of thepresent disclosure described below and illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to same or like parts.

For purposes of this disclosure, an “endoscope” may refer to anysuitable type of scope for insertion into a patient during a medicalprocedure. Endoscopes may include, for example, colonoscopes,duodenoscopes, gastroscopes, sigmoidoscopes, enteroscopes,ureteroscopes, and bronchoscopes. The term “procedure” broadly refers tothe insertion of an endoscope into a patient for any purpose, including,but not limited to, surgery, biopsy, diagnosis, treatment,visualization, implantation or removal of a device, suction, orinsufflation.

Prior to providing a detailed description, the following overviewgenerally describes the contemplated embodiments. Endoscope tip assembly17 of the current disclosure is configured to attach to a distal end ofan endoscope and to assume a streamline profile upon insertion of theendoscope within a body lumen and to assume an expanded configurationupon withdrawal of the endoscope to enlarge the body lumen to facilitateinspection of a region of interest.

Endoscope tip assembly 17 includes an attachment base 4. Base 4 isconfigured to receive a distal end of an endoscope so that an innersurface of base 4 attaches to an outer tip of the endoscope.Accordingly, base 4 may be sized so that the inner diameter is slightlylarger than the diameter of the tip of the endoscope tip and has acomplimentary shape. Specifically, base 4 is configured to be receivedon a rigid tip of the endoscope, as discussed further below, and may beslid, twisted, or friction-fit into place. The outer surface of the basemay serve as a support for the bottom surface of struts on withdrawal,as explained further below.

Base 4 may be present as a single unit attached to struts 3 and webbing2, as discussed below. Base 4 may include separate parts, for exampleshaft sleeve 22 and sleeve lock 23, discussed below. Alternatively, base4 may include shaft sleeve 30 and sleeve lock 25. In another embodiment,base 4 may include shaft sleeve 27, sleeve lock 26, and strut supportring 28. In a further embodiment, base 4 may include shaft sleeve 27 anddistal cap 29. In the aforementioned embodiments, the components workcooperatively to provide a support to struts 3 and webbing 2 and tofirmly grip the tip of the endoscope, to prevent the endoscope tipassembly from dislodging during a procedure.

Base 4 may include a plurality of gripping windows 19 or a plurality ofpressure pads 24. Upon withdrawal, struts 3 may bear or press ongripping windows 19 or pressure pads 24. As struts 3 apply pressure toeither gripping windows 19 or pressure pads 24, the force may increasesliding friction between either gripping windows 19 or pressure pads 24and the outer surface of the rigid tip of the endoscope. Thisself-locking action leading to increased friction may aid in preventingendoscope tip assembly 17 from disengaging from an endoscope during aprocedure.

Webbing 2 and struts 3 thickened cooperatively define a collapsibleumbrella portion extending out from base 4.

Struts 3 may have a flat shape in cross-section having a major axis anda minor axis. In other words, struts 3 may be elongated so that athickness in a direction normal to the surface of base 4 is smaller thanthe circumferential width of base 4. Further, the tips of struts 3 mayhave a bending shape. The struts 3 may extend from base 4 and may beconfigured to flex relative to base 4 in order to assume a morestreamlined, collapsed profile upon insertion into a body lumen and anenlarged, expanded profile upon withdrawal. In the collapsedconfiguration, struts 3 may be configured to fold so that they aresubstantially parallel with an axis of the endoscope to which endoscopetip assembly 17 is attached. In the expanded configuration, struts 3 maybe configured to extend away from the axis of the endoscope and towardsthe periphery of the body lumen in order to gently push on the bodylumen into which the endoscope is inserted. Accordingly, when expanded,struts 3 may apply pressure to the circumference of the body lumen inorder to enlarge the body lumen in a region surrounding endoscope tipassembly 17.

Struts 3 extend along webbing 2, forming a surface connected with struts3, similar in manner to how the material of an umbrella extends betweenthe ribs of the umbrella. Webbing 2 may extend along all or along aportion of the length of struts 3. Webbing 2 may extend all the way downthe length of struts 3 to connect with base 4. Webbing 2 may lie flushwith the tips of struts 3. Webbing 2 may cover only a portion of thestruts leaving a length 31 between the tips of struts 3 and the distaledge of webbing 2. Webbing 2 may extend beyond the tips of struts 3.

By extending between the tips of struts 3 and connecting struts 3 withone another, webbing 2 distributes the force applied to the body lumenby struts 3 more evenly across a larger surface area when in theexpanded configuration. Instead of struts 3 applying elevated pressureto the body lumen, which may cause trauma to the lumen, webbing 2 andstruts 3 cooperatively create a continuous contact surface. Over thecontact surface, the force of the expanded struts 3 is distributed alongthe periphery of the body lumen.

Accordingly, instead of resulting in a few high-pressure contact regionscentralized around the contact area of struts 3, the disclosed devicecreates a larger, diffuse, lower-pressure contact region similar to thatof some balloon devices.

For example, the combined calculated area of eight struts 3 in thedepicted embodiment may be approximately 480 mm, and the calculatedtotal area of webbing 2 may be approximately 1,670 mm². However, apassive endoscope tip assembly 17 lacks the technical limitations anddifficulties of such active balloon devices. Exemplary embodiments anddetails of endoscope tip assembly 17 are described further below.

Reference is now made to FIG. 1, which illustrates an exemplaryendoscope tip assembly 17, in a resting state, in accordance with anembodiment of the disclosure. Endoscope tip assembly 17 includes base 4.As discussed above, base 4 may be configured to fit onto and attach to adistal end of an endoscope. Base 4 is designed to prevent endoscope tipassembly 17 during use from detaching from an endoscope when maneuveredwithin a body lumen. To this end, base 4 may include texturing,protrusions, and/or pressure points, for example, to increase frictionbetween the inner surface of base 4 and an outer surface of theendoscope tip.

As shown in FIG. 1, the exemplary endoscope tip assembly 17 may includeone or more crush ribs 11. Crush ribs 11 may protrude from the innersurface of base 4 to contact the endoscope and may increase contactpressure between base 4 and the endoscope tip. Thereby increasingsliding friction to prevent endoscope tip assembly 17 from disengagingfrom the endoscope during a procedure. Crush ribs 11 may extend along anaxis of base 4 or may extend at an angle to or perpendicular to theaxis. Crush ribs 11 may include a plurality of discrete ribs or mayextend from one end of base 4 to the other or around the fullcircumference of base 4.

In some embodiments, crush ribs 11 may form a circular or screw-likedesign around the circumference of base 4. In some embodiments, crushribs 11 may be parallel to one another, at an angle to one another, orin any suitable arrangement to increase friction. Crush ribs 11 maytaper at one end, e.g., the proximal end, into a funnel or conicalshape. This may facilitate engagement with the rigid distal portion ofthe endoscope to which endoscope tip assembly 17 is attached. Further,crush ribs 11 may be solid or hollow or may have both solid and hollowregions.

Crush ribs 11 may be configured to deform slightly upon engagement withthe endoscope or when pressure is applied to endoscope tip assembly 17during removal of the device from the endoscope or during withdrawal ofthe endoscope in the body. Crush ribs 11 may be formed of any suitablematerial, discussed below. Crush ribs 11 may protrude from the innersurface of base 4 by a suitable amount, for example, ranging from about0.2 mm to about 0.7 mm. The inner diameter including crush ribs 11 maybe smaller than the outer diameter of the scope, discussed below. Theinner diameter of endoscope tip assembly 17 including crush ribs 11 mayaccordingly range from about 12.75 mm to about 15 mm for an adultdevice, and from about 8.75 mm to about 12 mm for a pediatric device,depending on the durometer of the material(s) that base 4 and crush ribs11 are made of. Without crush ribs 11, base 4 may have a diameterranging from about 12.25 mm to about 15 mm for an adult device, and fromabout 8.25 mm to about 12 mm for a pediatric device. The inner diameterof base 4 may be the same diameter as the surface upon which crush ribs11 are attached, such that the two surfaces are flush. In anotherembodiment, the inner diameter of base 4 may be a different diameterthan the diameter of the surface upon which crush ribs 11 are attached.

Exemplary material(s) that may be used to form base 4 and crush ribs 11include thermoplastic elastomers (e.g., polyurethane or santoprene(registered trademark)), thermosets (e.g., rubber and silicone rubber),or any other suitable material. The hardness durometer of thematerial(s) that base 4 and crush ribs 11 are formed of may range fromabout 20 A to about 70 A.

Alternatively, the inner surface of base 4 may be substantially smoothor may include a textured pattern that extends across the inner surfaceof base 4 and may not include crush ribs 11. For example, the innersurface may include a coating or texturing that maintains the placementof endoscope tip assembly 17 on an endoscope. In some embodiments, base4 and/or the inner surface of base 4 may be formed of a material with ahigher coefficient of friction. Or, in some embodiments, the smooth ortextured surface may further include one or more crush ribs 11.

An outer surface of base 4 may include one or more ridges, protrusions,indents, and/or textures to assist the clinician with attaching andremoving endoscope tip assembly 17 to and from an endoscope. Forexample, as is shown in FIG. 1, base 4 may include one or more dimples12 located around the outer perimeter of base 4. Dimples 12 may aid theclinician in gripping base 4 when endoscope tip assembly 17 is installedonto or removed from an endoscope.

The overall size and shape of base 4 may be based on the size and shapeof the distal end of the endoscope on which the tip assembly 17 isconfigured to attach. Exemplary endoscopes may range in diameter fromapproximately 13 mm to about 15 mm for adult endoscopes, while apediatric endoscope may have a tip diameter ranging from about 9 mm toabout 12 mm. In some embodiments, the inner diameter of base 4 may bebetween about 10 mm and about 14 mm. Further, the outer diameter of base4 may be configured to protrude only slightly from the surface of theendoscope onto which it fits so as to not substantially increase thediameter of the endoscope tip in order to facilitate insertion whenendoscope tip assembly 17 is in the collapsed, insertion configuration.For example, the outer diameter of base 4 may be about 11 mm to about 17mm. In some embodiments, base 4 of the endoscope tip assembly 17 maycome in a variety of sizes, for example, depending on the size and/orshape of an endoscope that the device is intended for use with.

Base 4 may be dimensioned so that when mounted on an endoscope,endoscope tip assembly 17 engages only a distal-most portion of theendoscope. The distal-most portions of many endoscopes include a rigidcylindrical tip, which may be made of rigid plastic or metal, to definethe end of the endoscope, provide rigidity, and/or to encase or protectthe optics and other structures located on the distal face of theendoscope. A bending portion of the endoscope is generally locatedproximal to this distal metal ring. The bending portions of mostendoscopes are more flexible and are generally made of more delicatematerials. It may thus be easier to puncture or damage these bendingportions, which may cause leakage or may otherwise damage or compromisethe integrity of the endoscopes. Given the expense of endoscopes, thiswould be undesirable and, if the damage occurs during use, this mayinterrupt or render the ongoing procedure impossible.

Accordingly, it may not be desirable to slide an endoscope accessoryover the bending portion or otherwise affix a device directly to thebending portion of an endoscope, either on a regular or occasionalbasis. To ameliorate this problem, endoscope tip assembly 17 is designedto interact with the rigid tip of the endoscope instead of the moredelicate bending portion. Thus, base 4 may be dimensioned to mate withthe rigid tip of the endoscope without overlapping the bending portion.Additionally, because endoscope tip assembly 17 sits at the distal tipof an endoscope, this may provide better visibility. This is because thebody lumen may be expanded at a region closer to the distal face of theendoscope where the optics are located.

Yet other devices typically are designed to affix to the bending portionin order to prevent them from disengaging from the endoscope during use.It was generally thought that an endoscope accessory should interactwith and affix to more than simply the tip of an endoscope in order tokeep the accessory in place. While other devices may be configured forplacement further back on endoscopes or may assume a wider dimension toincrease the contact area with the endoscopes to resist detachmentduring use, embodiments of the disclosed device may be narrower andconfigured to contact the distal, rigid ridge predominantly orexclusively while remaining in place on an endoscope. This may beachieved via, e.g., the use of crush ribs 11 and/or other designs, aswill be discussed further below. In some embodiments, the intendedplacement of endoscope tip assembly 17 on only the rigid portion of theendoscope may allow for the provision of a tighter friction-fit. Becausethe design does not need to take account of the delicateness of thebending portion. This may also allow base 4 to be more rigid. Thestiffness of base 4 may also aid with removal by allowing the clinicianto grip and apply pressure to the assembly without also applyingpressure to the underlying endoscope and increasing friction betweenendoscope tip assembly 17 and the endoscope.

Endoscope tip assembly 17 includes a collapsible umbrella extendingradially out from base 4. The umbrella is formed of webbing 2 and theplurality of flexible struts 3 configured to flex to transition thecollapsible umbrella between insertion, resting, and withdrawal states.

Endoscope tip assembly 17 may include about one to about twenty struts 3attached anywhere on base 4. For example, there may be three, four,five, six, eight, or twelve struts 3 attached to base 4. The struts 3are flexible and are configured to flex between a resting position, aninsertion position, and a withdrawal position. In the insertionposition, as shown in FIG. 7A, struts 3 are configured to flex in aproximal direction along the axis of the endoscope. This results in astreamlined profile for facilitating insertion of the endoscope into thebody.

Once inserted into a body lumen and guided to a region of interest, theendoscope may be slowly withdrawn to visualize the region of interest.As the endoscope is withdrawn, struts 3 may engage the body lumen andflex out from the axis of the endoscope. As the endoscope is furtherwithdrawn, struts 3 may flex until the tips of struts 3 point in adistal direction, as shown in FIG. 8. This is the withdrawal position.When not in use, endoscope tip assembly 17 may assume the restingposition, as shown in FIG. 1, in which struts 3 are biased to flare outfrom the axis of the endoscope. The natural outward biasing of struts 3in the resting position may facilitate the transition between theinsertion and the withdrawal positions inside the body lumen.

In some embodiments, when endoscope tip assembly 17 is in the restingposition, the total strut span may range from about 30 mm to about 70mm. When endoscope tip assembly 17 is in the insertion position, thetotal strut span may range from about 12 mm to about 18 mm. Theaforementioned strut span may vary depending upon the procedure and thepatient. For example, the average diameter of the upper gastrointestinaltract lumen may be different from the average diameter of the lowergastrointestinal tract or of other body lumens. Additionally, theaverage diameter of the same body lumens in an infant or youth may bedifferent than that of an adult. Accordingly, the strut span may reflectintended application, or even a particular patient, as appropriatesizing of the strut span will facilitate effective engagement with thelumen without applying an undesirable amount of pressure to the lumen.

The struts 3 support webbing 2 to transition webbing 2 between acollapsed insertion state (similar in profile to a collapsed umbrella)and a flipped, withdrawal state (similar in profile to an inside-outumbrella). As previously described, webbing 2 and struts 3 workcooperatively to create a diffuse, high-surface-area, low-pressurecontact region with the body lumen when in the withdrawal state, similarin manner to how a balloon would apply pressure to a lumen. For example,reference is made to FIG. 9A. The portion of endoscope tip assembly 17that contacts the body lumen is spread out over a greater surface areacreated by webbing 2 and struts 3, as opposed to, for example, thesurface of struts 3 alone. The diffuse contact region in FIG. 9A createdby endoscope tip assembly 17 is similar to the diffuse contact regioncreated by an endoscope equipped with a balloon.

In one embodiment, when in the resting position, there may be slack inwebbing 2 between adjacent struts 3, as shown in FIG. 1. Alternatively,as is shown in FIG. 2, there may be substantially no slack betweenadjacent struts 3. Webbing 2 may have a pleated pattern 1, asillustrated in FIG. 1. Alternatively, webbing 2 may have a non-pleatedpattern, as illustrated in FIG. 2. In either the pleated or non-pleatedembodiment, webbing 2 may extend flush with the ends of struts 3, asshown in FIGS. 1 and 2, or may extend past the ends of struts 3. In someembodiments, webbing 2 may extend flush with struts 3 where it joins theends of struts 3 but extend beyond them in a region between struts 3, orvice versa.

In one embodiment, webbing 2 and struts 3 of the collapsible umbrellamay be formed of different materials. For example, webbing 2 and struts3 may be attached to each other by an adhesive. In some embodiments, theadhesive may be a room temperature vulcanizing (RTV) adhesive. Inanother embodiment, webbing 2 and struts 3 may be attached to each otherby plastic or radio-frequency welding. In a further embodiment, webbing2 and struts 3 may be uniformly molded. In one embodiment, webbing 2 mayrange from about 0.05 mm to about 0.2 mm in thickness.

In some embodiments, gap 21 may be present in embodiments in whichwebbing 2 does not extend down struts 3 to meet with base 4. This gap 21may allow fluids and gases to pass through when endoscope tip assembly17 is in the withdrawal position and when struts 3 and webbing 2 areengaged with the lumen. In other embodiments, gap 21 may be absent. Insome embodiments, the distance between base 4 and the distal edge ofwebbing 2 may be between about 1 mm and about 6 mm.

In some embodiments, base 4 may include the plurality of dimples 12. Aspreviously mentioned, dimples 12 may facilitate gripping of endoscopetip assembly 17 by the clinician, which may aid in the installation ontoand removal from an endoscope. However, dimples 12 shown in FIG. 1 areexemplary. Any suitable design or pattern that aids the clinician ingripping endoscope tip assembly 17 is contemplated by this disclosure,such as, ridges, grooves, or a textured finish or material on the outersurface of base 4.

Webbing 2, struts 3, base 4, or crush ribs 11 may be made of the samematerial or different materials. Suitable materials include, thermosets(e.g., rubber or silicon rubber), thermoplastic elastomers (e.g.,thermoplastic polyurethane or santoprene (registered trademark), orother suitable biocompatible materials. Webbing 2 may also be made ofthermoplastic polyurethane film, any suitable polymer, or any suitablebiocompatible materials. One or more of webbing 2, struts 3, base 4, andcrush ribs 11 may also include a suitable coating, e.g., a lubricious oranti-bacterial coating.

Reference is now made to FIG. 3 and FIG. 4, which illustrate distal andproximal views, respectively, of endoscope tip assembly 17, drawnwithout webbing 2 for clarity, according to another embodiment of thedisclosure. In these views, the inner surface of an exemplary base 4 canbe viewed more clearly. As shown, struts 3 are attached to base 4 at aninner surface of base 4, extend from the inner surface of base 4 over anedge of base 4, and expand outwards from base 4 to the tips of struts 3.The struts 3 extend from the inner surface of base 4, over an edge ofbase 4, and flare outwards from base 4 to the tips of struts 3.

The struts 3 may be more flexible than base 4, which, in someembodiments may be rigid. The attachment of struts 3 to base 4 will bedescribed in detail further below. As discussed previously and shownhere in more detail, crush ribs 11 may increase the sliding frictionbetween a rigid endoscope tip and endoscope tip assembly 17. Crush ribs11 are exemplary, and other means for increasing sliding friction arecontemplated, as discussed above, including, for example, ridges, ortexturing.

In some embodiments, struts 3 may be more flexible than base 4, whichmay be rigid. In some embodiments, the struts may be made out ofsilicone and base 4 may be made out of polycarbonate or polysulfone.These materials are of substantial stiffness, are of medical grade, arecapable of being injection molded, and have a high glass transitiontemperature to allow for quick curing of silicone struts during siliconeovermolding.

Crush ribs 11, if included may extend along struts 3, between struts 3,or both. Crush ribs 11 may be separated from struts 3 and/or base 4, ormay be formed as part of one or the other of struts 3 or base 4, orboth, e.g., in the event that all three are formed of one material.

Further, as shown in FIG. 4, crush ribs 11 may extend along a surface ofthe struts 3 where the base of the struts 3 attaches to and projects outfrom the inner surface of base 4. In such an embodiment, crush ribs 11may form a funnel for easier engagement with the scope tip. In someembodiments, crush ribs 11 may be made of the same material as base 4and/or struts 3. In other embodiments, crush ribs 11 are made of adifferent material from that of base 4 and/or struts 3.

Reference is now made to FIG. 5, which illustrates a generic endoscopedevice 10. Endoscope control portion 6 may include knobs and dials thata clinician uses to guide tip 9 in a patient through controlled bendingof bending portion 7, found at the distal region of insertion tube 5.Insertion tube 5 is a long, flexible tube that bends as endoscope 10 isinserted into the patient. Bending portion 7 is controlled, remotely, bythe clinician and bends to navigate the turns of a lumen. Rigid tip 9,the distal-most portion of endoscope 10, houses, e.g., camera face 8.Rigid tip 9 is where endoscope tip assembly 17 of the present disclosuremay be affixed. Endoscope tip assembly 17 of the present disclosure maynot extend onto bending portion 7. This is because, as extending ontobending portion 7 may interfere with the clinician's ability to controlthe bending of bending portion 7 or may harm bending portion 7, asdescribed above.

Reference is now made to FIG. 6, which illustrates endoscope tipassembly 17 mounted on endoscope 10, in a resting state, according to anembodiment of the disclosure. In this embodiment, the distal edge ofbase 4 is flush with camera face 8 of the endoscope 10. This positionmay help to ensure that endoscope tip assembly 17 sits only on the tip 9and may not interfere with the operation of bending portion 7 ofendoscope 10. However, in some embodiments, base 4 may be set backslightly from the face of the endoscope. In some embodiments, the anglebetween struts 3 and the longitudinal axis of base 4 may be betweenabout 45° and about 90° in the resting state.

Reference is now made to FIG. 7A, which illustrates an endoscope tipassembly mounted on endoscope 10, in an insertion state. In someembodiments, the angle between struts 3 and a longitudinal axis ofendoscope 10 may be between about 0° and about 45°. It is advantageousfor struts 3 and webbing 2 to collapse into this position duringinsertion so that a smaller overall diameter is achieved for ease ofinsertion. The force to flex struts 3 and webbing 2 into the insertionposition may be less than the force required to flex struts 3 andwebbing 2 into a withdrawal position, as discussed below. Only a portionof the thickness of each strut 3 may need to be bent to transition thestrut from the resting position into the insertion position. Thisthickness may range from about 0.5 mm to about 1 mm. On the other hand,more of the thickness of each strut 3 or the whole of the thickness ofeach strut 3 may need to be bent to invert struts 3 into the withdrawalposition. This thickness may range from about 1 mm to about 3 mm.

Reference is now made to FIG. 7B, which illustrates an endoscope tipassembly mounted on endoscope 10, in a withdrawal position. Whenendoscope tip assembly 17 is in such a position, there may be slack inwebbing 2 between struts 3, which results in a pleating or bunching ofwebbing 2, similar to the pleating and bunching of an umbrella in aclosed position, as illustrated in FIG. 7B. In another embodiment, thepleats may be pre-formed such that pleating is present when there is noslack in the webbing.

Reference is now made to FIG. 8, which illustrates endoscope tipassembly 17 mounted on endoscope 10, in a withdrawal state. In someembodiments, the angle between struts 3 and the longitudinal axis ofbase 4 may be between about 50° and about 180° in the withdrawal state,measured along a straight line extending from the tips of struts 3 tothe place where they meet base 4. The diameter of the inside-outumbrella shape created by struts 3 and webbing 2 in this position mayrange from about 20 mm to about 30 mm.

Endoscope tip assembly 17 assumes this position upon withdrawal of theendoscope by flipping inside-out like an umbrella from the insertionposition (similar in shape to a closed umbrella) depicted in FIG. 7A.Struts 3 may engage the body lumen as endoscope 10 is initiallywithdrawn, and this engagement in combination with withdrawal causesstruts 3 to flex outwards away from the endoscope and into thewithdrawal state. The inside-out umbrella shape of endoscope tipassembly 17 may contact the lumen and gently apply outward pressure tothe lumen, thereby resulting in less traumatic contact with the lumen bymaking contact with a larger surface area across a more diffuse region,as opposed to discreet points of contact at the tips of struts 3. Thecontact achieved using endoscope tip assembly 17 may be similar inmanner to the type of contact that would be achieved using the balloonof a balloon-equipped endoscope.

Reference is now made to FIG. 9A, which illustrates endoscope tipassembly 17 mounted on endoscope tip 9 (obscured from view), inside of acolon 16 in a withdrawal state. The inside-out umbrella shape may leadto less traumatic contact with the colon wall, as the outward force isevenly distributed around the perimeter of webbing 2, similarly to aballoon-equipped endoscope. As shown in FIG. 9A, in the withdrawalposition, endoscope tip assembly 17 applies a gentle pressure to thecolon, holding the colonic folds in a more open configuration, which mayimprove visualization. In this manner, the shape may assist inmaximizing the clinician's visualization by flattening the colonic foldsby the inside-out umbrella shape, thereby revealing surfaces that mayotherwise be obscured by these folds.

This shape may also assist in stabilizing the endoscope tip 9 so thatthe clinician may visually inspect the interior of the colon or performa procedure more easily. Additionally, by expanding outwards evenly onall sides of the endoscope, struts 3 and webbing 2 may center theendoscope in a central region of the lumen, helping to at leastpartially counteract the force of gravity and counteract the propensityof the endoscope tip to drop along the colon wall or to drag along thecolon wall during withdrawal.

Reference is now made to FIG. 9B, which illustrates an endoscope tipballoon mounted on an endoscope, inside of colon 16. Reference is madeto the similarity in the diffuse contact region between the balloon andthe colonic wall in FIG. 9B compared with that achieved by endoscope tipassembly 17 in FIG. 9A. However, the active balloon in FIG. 9B requiresadditional equipment to inflate and control the balloon, whereas thepassive endoscope tip assembly 17 in FIG. 9A does not require suchadditional equipment or control. Also, the passive endoscope tipassembly 17 is located right at the distal tip of the endoscope, whereasthe axial distance from the endoscope tip to the active balloon is muchlarger, potentially reducing the impact that fold opening has onimproved visualization behind folds.

Reference is now made to FIG. 10, which illustrates endoscope tipassembly 17 in an insertion state, with webbing 2 omitted for clarity,in accordance with an embodiment of the disclosure. The embodiment ofFIG. 10 depicts a plurality of gripping windows 19. Base 4 may includeany suitable number of gripping windows 19. For example, base 4 mayinclude zero, two, four, six, eight, ten, twelve, or more grippingwindows 19. In some embodiments, gripping windows 19 may providegripping assistance to the clinician as he or she mounts and dismountsendoscope tip assembly 17. Gripping windows 19 may be located anywhereon base 4 and may be made of the same, or different, material as base 4.

Reference is now made to FIG. 11, which illustrates endoscope tipassembly 17 in a position with struts 3 folded in an extreme withdrawalstate, with webbing 2 omitted for clarity, in accordance with anembodiment of the disclosure. In some embodiments, it may beadvantageous for endoscope tip assembly 17 to be able to assume thesmallest possible outer diameter when mounted on an endoscope duringwithdrawal, when viewed along the longitudinal axis of the endoscope. Aminimal outer diameter may be achieved by struts 3 folding toward, andpotentially past, the distal end of the endoscope. This configurationmay help prevent traumatic contact, for example, in a more narrow areaof a body lumen, e.g., upon final removal of the endoscope tip from theanus. Accordingly, in some embodiments, the struts may be able to flexin a distal direction to a position substantially parallel with an axisof the endoscope.

The force required for struts 3 to assume an insertion position, asillustrated in FIG. 10, is less than the force required for struts 3 toassume a withdrawal position, as illustrated in FIG. 8 and FIG. 11. Inone embodiment, the force required for struts 3 to flex into theinsertion position, as illustrated in FIG. 10 may range from about 0.3lb to about 0.4 lb. In another embodiment, the force required for struts3 to assume the withdrawal position, as illustrated in FIG. 11 may rangefrom about 2.6 lb to about 3.0 lb. The ratio of withdrawal stiffness toinsertion stiffness of struts 3 may range from about 5 to about 8.

Requiring a small insertion force to flex struts 3 into an insertionposition may help prevent mucosal trauma during the procedure. Duringinsertion, the endoscope tip is guided to a region of interest, and thusthe goal is to achieve a streamline profile with a smaller diameter tofacilitate navigation of endoscope. Endoscope tip assembly 17 is thusconfigured to be substantially parallel to an axis of the endoscope andis not intended to apply an outward pressure to the colon to enlarge thecolon in the insertion position.

By contrast, during withdrawal, endoscope tip assembly 17 extends awayfrom the axis of the endoscope to apply a force to the colon to enlargethe colon and aid in visualization. Thus, in the withdrawal position,struts 3 must be able to resist the force applied when the endoscope iswithdrawn and the friction applied by the body lumen as the endoscope isbeing withdrawn. While some flexibility in the withdrawal position maybe desirable to prevent trauma to the mucosa during the procedure, ifthey are too flexible in the withdrawal position, then struts 3 may flexcompletely distally, as shown in FIG. 11, which would fail to open upthe colon may obstruct the clinician's vision, and/or may fail tostabilize the endoscope tip in the center of the colon. The fact that alarger force may be required for endoscope tip assembly 17 to flip likean inside-out umbrella from an insertion position to a withdrawalposition may allow struts 3 and webbing 2 to maintain an umbrella-likeshape upon withdrawal, thus helping to improve visualization and tipstabilization. In some embodiments, a small ratio of insertion force towithdrawal force may be desirable.

Reference is now made to FIG. 12, which illustrates an enlarged sideview of a portion of endoscope tip assembly 17 in a resting state, withwebbing 2 omitted for clarity, in accordance with an embodiment of thedisclosure.

Positive stop 13 may assist strut 3 in maintaining position and shapeupon withdrawal. Positive stop 13 may help struts 3 and webbing 2maintain the inside-out umbrella shape upon withdrawal, as previouslydescribed.

Reference is now made to FIG. 13, which illustrates a close-up distalview of an endoscope tip assembly 17 in a resting state, with webbing 2omitted for clarity, in accordance with an embodiment of the disclosure.As previously discussed, crush ribs 11 may be included on the innersurface of base 4. Crush ribs 11 may assist in increasing the amount ofsliding friction between base 4 and an endoscope, which may in turnprevent endoscope tip assembly 17 from slipping off of the endoscopeduring a procedure.

Reference is now made to FIG. 14, which illustrates a side-view of anexemplary strut 3, in accordance with an embodiment of the disclosure.Strut 3 may exist in a variety of shapes and thickness. In someembodiments, the thickness along the length of strut 3 may vary, asindicated by angled portion 20 in FIG. 14. For example, angled portion20 of strut 3 is thinner than intermediate portion. Also, for example,the proximal end of strut 3 has a larger cross-sectional area than thedistal end. In some embodiments, the width of strut 3 may vary, e.g., asshown in FIG. 14, and angled portion 20 may be narrower than base-mount14. Angled portion 20 has, for example, a width narrower than the widthof intermediate portion. This difference in thickness and/or width maygive rise to differences in flexibility and thus, differences in forcesrequired to flex different regions of strut 3. Alternatively, thethickness and/or width may be consistent along strut 3.

In some embodiments, the thickness of the straight portion of strut 3may range from about 0.5 mm to about 3.0 mm. In some embodiments, thethickness of angled portion 20 of strut 3 may range from about 0.5 mm toabout 1.0 mm. In some embodiments, the width of strut 3 may range fromabout 2 mm to about 5 mm, and strut 3 may have a uniform width or mayvary in width along the length.

In some embodiments, angled portion 20 of strut 3 may be angled outwardto intermediate portion in a non-biased state. In one embodiment, theangle of angled portion 20 of strut 3 may range from about 110° to about160°. If angled portion 20 is angled, it may help struts 3 to engagewith the lumen by catching on the surface of the lumen upon withdrawal.This increased engagement may assist struts 3 and webbing 2 to flipinside-out like an umbrella and thus achieve the withdrawal state. Atleast in part because the thickness of each strut tip is relativelythin, the stiffness of each of the strut tip is relatively low, and thestrut tip has a bending shape, endoscope tip assembly 17 is pliable andatraumatic when engaging the lumen and when in the withdrawal state. Ifstrut 3 has a flat plate shape, strut 3 is easily bent in a thicknessdirection but hardly deformed in a width direction. Therefore, when aninsertion portion of an endoscope is drawn out of a body, strut 3 isless likely to twist and buckle in a circumferential direction and canbe appropriately deformed in the drawing direction.

The struts 3 and webbing 2 are configured to make contact with thesurrounding body lumen during withdrawal, in an effort to stabilize thetip of the endoscope and to improve visualization. Additionally, struts3 must interact with the body lumen to transition from the insertionposition to the withdrawal position. Therefore, the length of struts 3is dictated, at least in part, by the diameter of the body lumen intowhich it will be inserted. In some embodiments, the length of struts 3from positive stop 13 to the outermost tip may range from about 10 mm toabout 25 mm.

Reference is now made to FIG. 15, which illustrates a side-view of strut3, in accordance with an embodiment of the disclosure. In thisembodiment, strut 3 includes one or more notches 15. Notches 15 may giverise to a difference in stiffness of strut 3 between a proximal-facingsurface and a distal-facing surface of strut 3. For example, the surfaceof strut 3 with notches 15 may require less force to bend inwards onitself than a surface of strut 3 without notches 15. In someembodiments, this difference between one surface of strut 3 and theother may allow strut 3 to preferentially bend in one direction over theother.

In some embodiments, there may be one or more notches 15 in strut 3. Insome embodiments, notches 15 may be located only on the straight portionof strut 3. In other embodiments, the notches may be located on both thestraight portion and angled portion 20 of strut 3. In other embodiments,there may be no notches 15, as illustrated in FIG. 14. Notches 15 mayhave any suitable shape, e.g., slits, rectangular, triangular, U-shaped,or tapered in cross-section. Gaps formed on the notched surface allowthe surface to collapse in on itself and the shape of the notches maythus affect the flexibility of strut 3.

Reference is now made to FIG. 16, which illustrates an angled view ofthe distal end of endoscope tip assembly 17, with notches 15 in struts3, where webbing 2 has been omitted for clarity, in accordance with anembodiment of the disclosure. FIG. 16 illustrates that, when notches 15are present in struts 3, struts 3 assume a resting position similar tothat of struts 3 without the notches, as illustrated in FIG. 3.

Reference is now made to FIG. 17A, which illustrates endoscope tipassembly 17 mounted on endoscope 10 in a resting state, in accordancewith an illustrative embodiment of the disclosure. Shaft sleeve 22 andsleeve lock 23 may work cooperatively to prevent an endoscope tipassembly 17 from disengaging from an endoscope and to provide supportand rigidity to struts 3 during withdrawal. Sleeve lock 23 may betapered such that the inner diameter of the distal end may be slightlygreater than the inner diameter at the proximal end. In one embodiment,the distal end of sleeve lock 23 may have a diameter ranging from about13.8 mm to about 15.5 mm. In another embodiment, the proximal end ofsleeve lock 23 may have a diameter of about 12.8 mm to about 15.0 mm.Like sleeve lock 23, shaft sleeve 22 may also be tapered, with the outerdiameter of the proximal end of shaft sleeve 22 being slightly largerthan the outer diameter of the distal end. In one embodiment, the outerdiameter of the distal end may range from about 13.3 mm to about 15.5mm. In another embodiment, the outer diameter of the proximal end mayrange from about 13.8 mm to about 16 mm. The tapered nature of bothshaft sleeve 22 and sleeve lock 23 may aid in increasing slidingfriction between shaft sleeve 22 and rigid tip 9 during withdrawal, whenthe struts may be forced to flex in a distal direction and press onsleeve lock 23. The tapered sections may engage, increasing the pressureand friction force between shaft sleeve 22 and rigid tip 9. This mayprevent endoscope tip assembly 17 from disengaging from an endoscope.

Reference is now made to FIG. 17B, which illustrates an angled view of apart of an exemplary endoscope tip assembly mounted on an endoscope in aresting position, according to an embodiment of the disclosure. Theangled view illustrates a difference in thickness between the proximaland distal ends of sleeve lock 23, and how it makes contact with shaftsleeve 22. In one embodiment, shaft sleeve 22 and sleeve lock 23 may bemade out of the same material. In another embodiment, shaft sleeve 22and sleeve lock 23 may be made out of different materials. The width ofsleeve lock 23 may range from about 2 mm to about 10 mm.

Reference is now made to FIG. 18A, which illustrates an exemplaryendoscope tip assembly mounted on an endoscope in a resting position,according to an embodiment of the disclosure. In one embodiment aplurality of pressure pads 24 may be present. In some embodiments, theremay be from about four pressure pads 24 to about twelve pressure pads24. Upon withdrawal, struts 3 may press on and apply pressure topressure pads 24. As pressure is applied to pressure pads 24, thesliding friction between base 4 and rigid tip 9 of endoscope 10 mayincrease, and thus may prevent endoscope tip assembly 17 from fallingoff during a procedure.

Reference is now made to FIG. 18B, which illustrates an angled view of apart of an exemplary endoscope tip assembly mounted on an endoscope in aresting position, according to an embodiment of the invention. Thisangled view illustrates the contact between sleeve lock 25, pressure pad24, and a shaft sleeve 30. As previously mentioned, during withdrawal,struts 3 may press against and apply pressure to pressure pads 24, whichmay in turn increase pressure between shaft sleeve 30 and rigid tip 9 ofendoscope 10. In one embodiment, shaft sleeve 30 and sleeve lock 25 maybe separate pieces. In another embodiment, shaft sleeve 30 and sleevelock 25 may be one piece. In one embodiment, the length of each pressurepad 24 may range from about 2 mm to about 7 mm. In another embodiment,the width of each pressure pad 24 may range from about 2 mm to about 5mm.

In one embodiment, shaft sleeve 30 and sleeve lock 25 may be made fromthe same material. In another embodiment, shaft sleeve 30 and sleevelock 25 may be made of different materials.

Reference is now made to FIG. 19A, which illustrates a partiallyexploded view of an exemplary endoscope tip assembly in a restingposition, according to an embodiment of the disclosure. In oneembodiment, base 4 may include shaft sleeve 27, sleeve lock 26, andstrut support ring 28. These three pieces may work cooperatively toincrease sliding friction between shaft sleeve 27 and rigid tip 9 ofendoscope 10 to prevent endoscope tip assembly 17 from falling offduring a procedure, and/or to provide a rigid surface upon which struts3 may push during withdrawal. This arrangement may provide for adisengagement force that is greater than the force required to frictionfit endoscope tip assembly 17 onto the endoscope tip. In one embodiment,the coefficient of friction between sleeve lock 26 and shaft sleeve 27may be less than the coefficient of friction between shaft sleeve 27 andrigid tip 9. Sleeve lock 26 may include crush ribs 11, which may serveto apply additional pressure on shaft sleeve 27, thereby increasingsliding friction between shaft sleeve 27 and rigid tip 9 of theendoscope 10.

In one embodiment, shaft sleeve 27, sleeve lock 26, and strut supportring 28 may be made of the same material. In another embodiment, shaftsleeve 27, sleeve lock 26, and strut support ring 28 may be made ofdifferent materials. Crush ribs 11 have properties as previouslydiscussed.

The inner diameter of sleeve lock 26 is tapered, increasing toward theproximal end. The taper angle may range from about 0.50 to about 2.50.The outer diameter of shaft sleeve 27 is also tapered in the samedirection, with a diameter of the distal end that is smaller than thediameter of the proximal end. The taper angle of shaft sleeve 27 mayvary from about 0.50 to about 2.5°.

In one embodiment, the inner diameter of the distal end of sleeve lock26 may be identical to the outer diameter of the distal end of shaftsleeve 27. In another embodiment, the inner diameter of the distal endof sleeve lock 26 may be slightly less than the outer diameter of thedistal end of shaft sleeve 27. For example, in one embodiment, the innerdiameter of sleeve lock 26 may be from about 14 mm to about 16 mm for anadult colonoscope. In another embodiment, the outer diameter of shaftsleeve 27 may be from about 14 mm to about 15.5 mm. In one embodiment,the width of sleeve lock 26 may be about the same as the width of shaftsleeve 27. In another embodiment, the width of sleeve lock 26 may bedifferent from the width of shaft sleeve 27. In one embodiment, thewidth of sleeve lock 26 may be from about 5 mm to about 10 mm. Inanother embodiment, sleeve lock 26 may have a thickness ranging fromabout 0.4 mm to about 1.5 mm. In another embodiment, shaft sleeve 27 mayhave a thickness from about 0.3 mm to about 0.75 mm. In one embodiment,strut support ring 28 may have a thickness ranging from about 0.3 mm toabout 1.0 mm.

Reference is now made to FIGS. 20A and 20B, which illustrate anexemplary endoscope tip assembly in a resting position, according to anembodiment of the disclosure. In one embodiment, base 4 may includedistal cap 29 and shaft sleeve 27. These two pieces may workcooperatively to increase sliding friction between shaft sleeve 27 andrigid tip 9 of endoscope 10 to prevent endoscope tip assembly 17 fromfalling off during a procedure, and/or to provide a rigid surface uponwhich struts 3 may push during withdrawal. Further, in extending pastthe end of endoscope 10, distal cap 29 may aid in holding back the lumensuch that a camera 8 has an unobstructed view. The inner diameter ofdistal cap 29 may be about the same as the outer diameter of shaftsleeve 27. In another embodiment, the inner diameter of distal cap 29may be different than the outer diameter of shaft sleeve 27. In oneembodiment, the inner diameter of distal cap 29 may range from about 12mm to about 17 mm. In another embodiment, the outer diameter of shaftsleeve 27 may be from about 13 mm to about 15 mm. In one embodiment,such as, for example, FIG. 20A, the width of distal cap 29 may beconsistent along the circumference and may range from about 2 mm toabout 8 mm. In another embodiment, such as, for example, FIG. 20B, thewidth of the distal cap may vary. In some embodiments, the width ofdistal cap 29 may vary along the circumference of the cap, where thewidth may range from about 2 mm to about 12 mm.

Reference is now made to FIG. 21A, which illustrates a cross-sectionview of a strut in an insertion position, according to an embodiment ofthe disclosure. Base 4 is permanently adhered to strut 3, as indicatedby A, but it is not permanently adhered strut 3 at C. During insertion,the insertion force f_(insertion) needed to flex struts 3 in a proximaldirection may be low compared to the force required during withdrawalF_(withdrawal). This is because the resistance r_(insertion), attemptingto maintain struts 3 in a resting position, is a cubic function of thethickness of strut 3, t_(insertion), and this thickness may range fromabout 30% to about 60% of the thickness of strut 3 during withdrawal,T_(withdrawal). Further, as endoscope tip assembly 17 is inserted, nocontact is made at C between positive stop 13 and base 4.

Reference is now made to FIG. 21B, which illustrates a cross-sectionview of a strut in a resting position, according to an embodiment of thedisclosure. In a resting position, a contact C exists between base 4 andpositive stop 13 of strut 3.

Reference is now made to FIG. 21C, which illustrates a cross-sectionview of a strut in a withdrawal position, according to an embodiment ofthe disclosure. Upon withdrawal, contact exists at C, between base 4 andpositive stop 13 of strut 3. Further, the resistance to flexing duringwithdrawal R_(withdrawal) is a cubic function of the total strutthickness during withdrawal T_(withdrawal), which may be much greaterthan the resistance at insertion r_(insertion). This withdrawalresistance R_(withdrawal) may assist in maintaining the invertedumbrella-like shape of struts 3 and webbing 2 upon withdrawal.

Reference is now made to FIG. 22, which illustrates an exemplaryendoscope tip assembly, with pleated webbing that does not extend to theend of the strut, according to an embodiment of the present disclosure.Length 31 represents the distance between the tip of strut 3 and theedge of webbing 2. In some embodiments, length 31 may be 0 mm, asillustrated in FIG. 1. In some embodiments, length 31 may range fromabout 0 mm to about 15 mm. In other embodiments, length 31 may rangefrom about 3 mm to about 10 mm. This length 31, when greater than 0 mmmay facilitate better visualization of the inside of the colon duringthe procedure, as there may be less webbing 2 to obstruct the camera'sview.

Reference is now made to FIG. 23, which illustrates an exemplaryendoscope tip assembly, according to an embodiment of the presentdisclosure. In the endoscope tip assembly illustrated in FIG. 23, oneend of pleated webbing 2 is connected with struts 3 at a position wherestrut 3 bends (where the angle between intermediate portion and angledportion 20 varies) and do not extend to angled portion 20 of strut 3.FIG. 23 provides an alternative view of the embodiment illustrated inFIG. 22, where length 31 is a non-zero distance. Webbing 2 not extendingto angled portion 20 provides resistance not too large when being drawnfrom a body. In such a configuration, the range in which struts 3 extendstraight is the connection range of webbing 2, and webbing 2 does notneed to follow the flexed shape of struts 3, facilitating manufacture.

Reference is now made to FIG. 24, which illustrates an exemplaryendoscope tip assembly mounted on an endoscope in a resting position,according to an embodiment of the disclosure. Length 31 may be 0 mm, asillustrated in FIG. 6, or, in some embodiments, length 31 may range fromabout 0 mm to about 15 mm, as illustrated in, for example, FIG. 24. Insome embodiments, the radial length of webbing 2 may range from about25% to about 100% of the length of the strut.

Reference is now made to FIG. 25A, which illustrates an exemplaryendoscope tip assembly mounted on an endoscope in a resting position,according to an embodiment of the disclosure. Length 31 may be 0 mm, asillustrated in, for example, FIG. 6, or, in some embodiments, length 31may range from about 0 mm to about 15 mm, as illustrated in, forexample, FIG. 24. In one embodiment, base 4 may include distal cap 29and shaft sleeve 27. These two pieces may work cooperatively to aid inholding back the lumen such that camera 8 has an unobstructed view. Inone embodiment, such as, for example, FIG. 25A, the width of the distalcap may be consistent along the circumference and may range from about 2mm to about 8 mm. In another embodiment, such as, for example, FIG. 25B,the width of distal cap 29 may vary along the circumference of the cap,where the width may range from about 2 mm to about 12 mm.

In one embodiment of the present disclosure, endoscope tip assembly 17is mounted on an endoscope, and endoscope tip assembly 17 is configuredsuch that an extraction force upon extraction of the endoscope from abody is larger than an insertion force upon insertion of the endoscopeinto the body (i.e., such that there is an insertion-extraction forcedifference). Here, the insertion-extraction force difference is definedas a difference obtained by subtracting the insertion force uponinsertion of the endoscope provided with endoscope tip assembly 17 intoa body, from the extraction force upon extraction of the endoscope fromthe body.

The insertion-extraction force difference varies depending on factors,such as the thickness, shape, or material of strut 3. In addition, theinsertion-extraction force difference correlates with the angle of strut3 relative to base 4 during extraction of the endoscope. Alternatively,the extraction force depends on the angle of strut 3 relative to base 4upon extraction of the endoscope. Endoscope tip assembly 17 includeswebbing 2 provided in gaps between struts 3, and the extraction forcefurther depends on the aforementioned configurations (mounting region,hardness (difference), area, etc.) of webbing 2.

The following Table 1 shows the results of measurement of the insertionand extraction forces of endoscope tip assemblies having struts 3different in thickness, shape, and the like. The insertion-extractionforces were measured as follows: each of the endoscope tip assemblieswas mounted to a push-pull gauge and inserted into each of 24-mm and29-mm inner diameter acrylic tubes (length L=150 mm), and maximum forceupon insertion and drawing out were measured, obtaining the insertionforce and the extraction force, respectively. Insertion and drawingspeeds were 75 mm/s. Further, the measurement was conducted by using theacrylic tubes having a plurality of inner diameters in consideration ofthe diversity of the diameters of the intestines.

TABLE 1 Insertion- Insertion Extraction extraction force force forceamount amount amount difference Insertability/ 24 29 24 29 24 29Observability #1 0.16 0.09 0.44 0.29 0.28 0.2 X #2 0.18 0.09 0.94 0.590.76 0.5 ◯ #3 0.26 0.13 2.08 1.21 1.82 1.08 ◯ #4 0.33 0.16 4.11 2.223.78 2.06 ◯ #5 0.48 0.25 6.09 3.11 5.61 2.86 ◯ #6 0.59 0.31 8.08 4.287.49 3.97 ◯ #7 0.78 0.39 9.88 5.42 9.1 5.03 ◯ #8 1.88 0.92 11.74 6.719.86 5.79 ◯ #9 5.44 3.08 18.44 10.4 13 7.36 X Unit: (N)

As described above, the insertability and the observability wereevaluated using a large intestine model created by imitating a largeintestine, for each of the endoscope tip assemblies #1 to #9 shown inTable 1. Here, the observability refers to an index indicating whetherthe large intestine may be observed preferably when an endoscope isdrawn out.

As for #1, a sufficient insertion-extraction force difference was notobtained, leading to a lack of observability, and as a result theinsertability and the observability were not balanced.

As for #2 to #8, good insertability and observability were obtained. Inparticular, for #3 to #6, good observability was always obtained duringthe evaluation of the observability (i.e., during the extraction of theendoscope from the large intestine model).

As for #8, poor drawability upon drawing out was obtained in places.

As for #9, the insertion-extraction force difference was excessive, andthe insertability and the observability were not balanced.

As described above, adjustment of the structure of endoscope tipassembly 17 may improve observability, such as increasing accuracy indetecting a lesion behind the folds of the intestine. As describedabove, it is important to balance the insertability and theobservability of the endoscope compatible.

<Modification of Crush Rib>

In recent years, due to diversification of doctors, such as activationof female doctors, there are demands for endoscope tip assemblies whichmay be easy to mount as well as prevented from dropping off. Furtherexamples of endoscope tip assemblies will be described below.

FIGS. 26A, 26B and 26C each illustrate an enlarged view of a portion ofinner surface of an endoscope tip assembly 17. In FIGS. 26A, 26B and26C, each endoscope tip assembly 17 includes a plurality of crush ribs11 on the inner surface which makes contact with an endoscope. Theplurality of crush ribs 11 is inclined in the direction of insertion ofthe endoscope, and crush ribs 11 each have a height increasing towardthe inside from the opening end side of endoscope tip assembly 17.Therefore, as endoscope tip assembly 17 is inserted, a resistance forceapplied to the endoscope from endoscope tip assembly 17 increases. Inother words, with the insertion into endoscope tip assembly 17, frictionforce in the direction of insertion increases.

On the other hand, when endoscope tip assembly 17 is removed from theendoscope, the most protruding portions of crush ribs 11 continue tomaking contact with the endoscope, and the friction force substantiallyconstant is applied until tip assembly 17 is withdrawn by a certainlength.

Therefore, endoscope tip assembly 17 including projection portion 11 ofthe aforementioned shape has a mounting force, required to mountendoscope tip assembly 17 to the endoscope, smaller than a dismountingforce, required to remove endoscope tip assembly 17 from the endoscope.

In the example illustrated in FIG. 26A, endoscope tip assembly 17 isprovided with a plurality of crush ribs 11 on the inner surface in thedirection of insertion of the endoscope. Such a configuration reducesthe mounting force required to mount endoscope tip assembly 17 to theendoscope, relative to the dismounting force required to removeendoscope tip assembly 17 from the endoscope.

In the example illustrated in FIG. 26B, crush ribs 11 have a widthsagittaly increasing toward the inside from the open end side ofendoscope tip assembly 17, on the inner surface of endoscope tipassembly 17. Such a configuration reduces the mounting force required tomount endoscope tip assembly 17 to the endoscope, relative to thedismounting force required to remove the endoscope tip assembly from theendoscope.

In the example illustrated in FIG. 26C, crush ribs 11 have a V-shapewhich is bifurcated toward the inside from the open end side ofendoscope tip assembly 17. Such a configuration reduces the mountingforce required to mount endoscope tip assembly 17 to the endoscope,relative to the dismounting force required to remove endoscope tipassembly 17 from the endoscope.

The following Table 2 shows the results of measurement of the mountingand dismounting forces of endoscope tip assemblies having differentthicknesses, sizes, number, shapes, and the like of crush ribs 11 ofFIG. 26B. The measurement was conducted according to the followingmethod.

1. Each of the endoscope tip assemblies was put on each of 13.1 mm and13.2 mm diameter pin gauges and inserted into the pin gauge by using apush-pull gauge from above a plastic board, and the maximum value of aforce upon insertion was measured (mounting force).

2. Each of the endoscope tip assemblies was mounted to each of 13.1 mmand 13.2 mm diameter pin gauges, a base of the endoscope tip assemblywas fixed, and the maximum value of a force upon drawing out the pingauge by using the push-pull gauge (dismounting force).

TABLE 2 Pin gauge Attachment force amount Detachment force amount size ϕ13.10 mm ϕ 13.20 mm ϕ 13.10 mm ϕ 13.20 mm #1 22.49 36.95 23.63 40.28 #223.61 39.21 24.10 40.04 #3 29.74 44.19 28.81 44.61 Unit: (N)

Endoscope tip assembly 17 was preferably mounted to the endoscope whenthe mounting force is 45 N or less.

Endoscope tip assembly 17 was preferably removed from the endoscope whenthe dismounting force is 20 N or more and 45 N or less.

When drawing the endoscope with endoscope tip assembly 17 from a body,the extraction force required to extract the endoscope with endoscopetip assembly 17 from the body needs to be smaller than the dismountingforce of endoscope tip assembly 17 so that endoscope tip assembly 17 isprevented from falling off. The extraction force is preferably 1 N ormore smaller than the dismounting force. In endoscope tip assembly 17, adifference between the dismounting force and the mounting force is morepreferably 3 N or less.

<Further Description of Resistance Force of Strut>

FIG. 27 is a graph schematically illustrating a relationship of theangle between strut 3 and base 4 according to one embodiment (it isdefined that the axial direction opposite to the direction of insertionof an endoscope tip is 0°, and angles counterclockwise to the axialdirection are positive) to a force required to tilt strut 3 from theproximal end side to the distal end side of the endoscope (theresistance force of the strut).

Steps (displacement points) in the graph showing the resistance forceare caused by the abutment of a recessed portion for receiving base 4 (aportion of the recessed portion abuts against base 4), removal of slackin webbing 2, a notch in strut 3, and the like. The above graph isidealized, and in endoscope tip assembly 17 which is made of an elasticmember, the curve is smoothed, and discontinuities constituting thesteps appear as inflection points of the curve. Struts 3 of endoscopetip assembly 17 in the present embodiment have a resistance forcevarying in multiple steps, supporting the folds in the wall of theintestine with a more optimal friction force.

In some embodiments, a method for improved visualization duringendoscopic procedures is provided, wherein an endoscope tip assembly ofthe present disclosure is mounted on the distal end of an endoscopeprior to the procedure.

In some embodiments, a method for improved endoscope stabilizationduring endoscopic procedures is provided, wherein an endoscope tipassembly of the present disclosure is mounted on the distal end of anendoscope prior to the procedure.

In some embodiments, a method for less traumatic endoscopic proceduresis provided, wherein an endoscope tip assembly of the present disclosureis mounted on the distal end of an endoscope prior to the procedure.

While the present disclosure is described herein with reference toillustrative embodiments of endoscope attachments used for particularapplications, such as for performing medical procedures, it should beunderstood that the embodiments described herein are not limitedthereto. For example, scopes and similar devices are often used inindustrial applications, e.g., to inspect and/or repair machinery.Endoscope attachments of the present disclosure may also be used withindustrial scopes in non-medical settings. Those having ordinary skillin the art and access to the teachings provided herein will recognizeadditional modifications, applications, embodiments, and substitution ofequivalents that all fall within the scope of the disclosed embodiments.Accordingly, the disclosed embodiments are not to be considered aslimited by the foregoing or following descriptions.

The many features and advantages of the present disclosure are apparentfrom the detailed description, and thus it is intended by the appendedclaims to cover all such features and advantages of the presentdisclosure that fall within the true spirit and scope of the presentdisclosure. Further, since numerous modifications and variations willreadily occur to those skilled in the art, it is not desired to limitthe present disclosure to the exact construction and operationillustrated and described. Accordingly, all suitable modifications andequivalents may be resorted to, falling within the scope of the presentdisclosure.

Moreover, those skilled in the art will appreciate that the conceptionupon which this disclosure is based may readily be used as a basis fordesigning other structures, methods, and systems for carrying out theseveral purposes of the present disclosure. Accordingly, the claims arenot to be considered as limited by the foregoing description.

Examples of the embodiments of the present disclosure will be describedbelow. These examples of the embodiments may be partially substituted orcombined with each another as long as no contradiction arises.

[1]

An endoscope tip assembly including a ring-shaped base receiving one endof an endoscope, and a plurality of struts collapsibly radiating awayfrom the base, in which the endoscope including the endoscope tipassembly has a larger extraction force upon extraction from a body thanan insertion force upon insertion into the body.

[2]

The endoscope tip assembly according to [1], in which an angle of eachof the struts relative to the base during extraction of the endoscopefrom the body correlates with an insertion-extraction force differencebeing a value obtained by subtracting the insertion force from theextraction force upon extraction from the body.

[3]

The endoscope tip assembly according to [2], in which theinsertion-extraction force difference ranges from 0.5 N to 10 N.

[4]

The endoscope tip assembly according to [2], in which theinsertion-extraction force difference ranges from 1.0 N to 4.0 N.

[5]

The endoscope tip assembly according to [2], in which theinsertion-extraction force difference ranges from 2.0 N to 3.0 N.

[6]

The endoscope tip assembly according to [1], in which the insertionforce is 5.0 N or less.

[7]

The endoscope tip assembly according to [1], in which the insertionforce is 2.0 N or less.

[8]

The endoscope tip assembly according to [1], in which the insertionforce is 0.5 N or less.

[9]

The endoscope tip assembly according to [1], in which the extractionforce ranges from 0.5 to 10 N.

[10]

The endoscope tip assembly according to [1], in which the extractionforce ranges from 1.0 N to 4.5 N.

[11]

The endoscope tip assembly according to [1], in which the extractionforce ranges from 2.0 N to 3.5 N.

[12]

The endoscope tip assembly according to [1], in which the extractionforce varies according to an angle of the plurality of struts relativeto the base.

[13]

The endoscope tip assembly according to [1], in which a webbing isprovided between each of the plurality of struts, and the extractionforce varies according to a material, shape, size, or arrangementposition of the webbing.

[14]

An endoscope tip assembly including a ring-shaped base receiving one endof an endoscope, and a plurality of struts collapsibly radiating awayfrom the base, in which each of the plurality of struts has a recessedportion receiving the base.

[15]

The endoscope tip assembly according to [14], further including awebbing restraining the respective struts.

[16]

The endoscope tip assembly according to [14], in which a portion of therecessed portion is fixed to an inner surface of the base, and anotherportion of the recessed portion engageably makes contact with the base.

[17]

The endoscope tip assembly according to [14], in which a force requiredto tilt each of the plurality of struts to which no external force isapplied, forward or backward relative to the endoscope tip assembly isproportional to the cube of a thickness of the strut.

[18]

An endoscope tip assembly including a ring-shaped base removably mountedto a distal end of an endoscope insertion portion, having an outer layerformed of a first polymer, and an inner layer formed of a second polymerhaving a smaller hardness than that of the first polymer, and aplurality of struts formed of the second polymer to collapsibly radiatefrom the base.

[19]

The endoscope tip assembly according to [18], in which a difference indurometer hardness between the struts and the outer layer is A10 ormore.

[20]

The endoscope tip assembly according to [19], in which the difference indurometer hardness is A30 or more.

[21]

The endoscope tip assembly according to [19], in which the difference indurometer hardness is A60 or more.

[22]

The endoscope tip assembly according to [18], in which the outer layerhas a durometer hardness of A70 or more.

[23]

The endoscope tip assembly according to [18], in which the outer layerhas a durometer hardness of A90 or more.

[24]

The endoscope tip assembly according to [18], in which the struts have adurometer hardness of A30 to A80.

[25]

The endoscope tip assembly according to [18], in which the struts have adurometer hardness of A40 to A70.

[26]

The endoscope tip assembly according to [18], in which the struts have adurometer hardness of A50 to A60.

[27]

The endoscope tip assembly according to [26], in which the struts andthe inner layer are formed of silicone rubber.

[28]

The endoscope tip assembly according to [18], in which the struts tilttoward the proximal end side of the endoscope in a state where no forceis applied to the struts.

[29]

The endoscope tip assembly according to [1], further including a webbingrestraining the respective struts.

[30]

The endoscope tip portion assembly according to [29], in which thewebbing is dimensioned to remove slack when an angle, definedclockwisely from the endoscope tip side, is 0° or more and 90° or less,and to have slack when the angle is larger than 900 and 180° or less.

[31]

The endoscope tip assembly according to [29], in which the webbing is aplanar member thinner than the struts.

[32]

The endoscope tip assembly according to [29], in which the webbing has athickness of 0.05 mm to 0.2 mm.

[33]

The endoscope tip assembly according to [29], in which the webbing isprovided having rotational symmetry to the plurality of struts, and thestruts and the webbing have a shape satisfying the following conditions.

(Conditions)

When x is a distance from an origin where the proximal position of astrut is defined as the origin, w(x) is a width of a webbing located atthe position x, s(x) is the width of the strut at the position x, n isthe number of the struts, r is a distance from the center of a base tothe proximal end position of the strut, and θ is an angle between theaxis of the base and the strut, 0°<θ<90° satisfies formula 1 within apredetermined range x.W(x)=2π(r+x sin θ)/n−s(x)  (Formula 1)

[34]

The endoscope tip assembly according to [29], in which 30°<θ<80°satisfies formula 1 within a predetermined range x.

[35]

The endoscope tip assembly according to [29], in which 45°<θ<70°satisfies formula 1 within the predetermined range x.

[36]

The endoscope tip assembly according to [1], in which when each of thestruts is tilted in a direction perpendicular to the direction ofinsertion of the endoscope from a state in which the struts fall on theproximal end side of the base, there is at least one change point wherea resistance force of the strut intermittently varies or anincrease/decrease rate in the resistance force varies.

[37]

The endoscope tip assembly according to [36], in which there is aplurality of the change points.

[38]

The endoscope tip assembly according to [36], further including awebbing restraining the respective struts, in which each of the strutsincludes a recessed portion receiving the base, and the resistance forceof the strut has a first change point corresponding to timing at which aportion of the recessed portion of the strut abuts against the base anda second change point corresponding to timing at which slack in thewebbing is removed.

[39]

An endoscope tip assembly including a ring-shaped base receiving one endof an endoscope, and a plurality of struts collapsibly radiating awayfrom the base, in which the endoscope including the endoscope tipassembly has a larger extraction force upon extraction from a body thanan insertion force upon insertion into the body, and has a smallermounting force required for mounting to the endoscope than a dismountingforce required for removal from the endoscope.

[40]

The endoscope tip assembly according to [39], in which the extractionforce is smaller than the dismounting force.

[41]

The endoscope tip assembly according to [39], in which the extractionforce is smaller than the dismounting force by at least 1 N.

[42]

The endoscope tip assembly according to [39], in which a differencebetween the dismounting force and the mounting force is 3 N or less.

[43]

The endoscope tip assembly according to [39], in which a differencebetween the dismounting force and the mounting force is 15 N or less.

[44]

The endoscope tip assembly according to [39], in which a differencebetween the dismounting force and the mounting force ranges from 0.5 Nto 10 N.

[45]

The endoscope tip assembly according to [39], in which the dismountingforce is 45 N or less.

[46]

The endoscope tip assembly according to [39], in which the mountingforce is 45 N or less.

[47]

An endoscope tip assembly including a ring-shaped base removably mountedto a distal end of an endoscope insertion portion, a plurality of strutscollapsibly radiating from the base, and a webbing connecting twoadjacent struts of the plurality of struts to each other, in which whenan angle, defined clockwisely from the distal end side of the endoscopeinsertion portion, is larger than 900 and 180° or less, the webbing hasan angle at which slack is removed.

The advantages of the endoscope tip assembly in the embodimentsaccording to [14], [15], [16], [39], and [40] described above will bedescribed below.

In an endoscope provided with the endoscope tip assembly according to[14], each of the plurality of struts includes the recessed portionreceiving the base portion, and when the endoscope is inserted into abody, each of the plurality of struts easily falls down on the proximalend side of the endoscope. In other words, when the endoscope isinserted into the body, each of the plurality of struts easily fallsdown on the opposite side of the tip of the endoscope. Therefore, theinsertion force required to insert the endoscope into the body isreduced.

In an endoscope provided with the endoscope tip assembly according to[15], as each of the plurality of struts falls down on the endoscope tipside, the angle between adjacent struts increases or adjacent struts areseparated from each other. Therefore, when falling down on the endoscopetip side relative to a predetermined position, each of the plurality ofstruts will receive a restraining force from the webbing and is unlikelyto fall down on the endoscope tip side relative to the predeterminedposition. In other words, the extraction force of the endoscope providedwith the endoscope tip assembly upon withdrawal from a body is largerthan that of an endoscope using an endoscope tip assembly without thewebbing.

In an endoscope provided with the endoscope tip assembly according to[16], a portion of the recessed portion of each strut engageably makescontact with the base portion, and when the endoscope is inserted into abody, each of the plurality of struts easily falls down on the proximalend side of the endoscope. More specifically, when the endoscope isinserted into the body, a surface, facing an outer surface of the baseportion, of the surface of the recessed portion is separated from theouter surface of the base portion, and each of the plurality of strutseasily falls down on the side opposite to the endoscope tip when theendoscope is inserted into the body. In addition, when each of theplurality of struts falls down on the endoscope tip side relative to apredetermined position, a base side contact surface of the base and arecessed portion contact surface of the recessed portion make contactwith each other and press against each other. Therefore, in theendoscope provided with an aforementioned endoscope tip assembly, theinsertion force upon insertion of the endoscope into the body is smallerthan the extraction force upon extraction of the endoscope from thebody. For example, the angle (predetermined position) of each strut atwhich a portion of the recessed portion and the base portion makescontact with each other is at a position where there is no slack in thewebbing and the strut falls down on the proximal end side of theendoscope relative to the angle at which the strut receives therestraining force from the webbing.

In an endoscope provided with the endoscope tip assembly according to[39], the endoscope tip assembly may be mounted to the endoscope withoutrequiring a large force, yet is hardly removed from the endoscope duringinsertion of the endoscope into a body. In addition, in an endoscopeprovided with the endoscope tip assembly according to [40] configured asdescribed above, when the endoscope is drawn out of a body, theendoscope tip assembly is hard to slip off of the endoscope.

A description will be given of [33] to [35] with reference to FIGS. 28Aand 28B. FIG. 28A is a side view of base 4 and struts 3. The outercircumference of an umbrella formed by struts 3 and webbing 2 at aposition located at a distance x from the proximal end (the end mountedto base 4) of strut 3 is expressed by 2π(r+x sin θ), where an innerdiameter of the base is r and an angle between strut 3 and base 4 is 8.Therefore, as illustrated in FIG. 28B, when the width of the strut atthe position at the distance x is s(x), the width of webbing 2connecting struts 3 at the position is w(x), and the number of thestruts is n, w(x)=2π(r+x sin θ)/n−s(x) represents that webbing 2 isstretched without slack. In other words, the conditions described in[33] to [35] mean requests for presence of the angle between strut 3 andbase 4 where webbing 2 has no slack, at a predetermined position ofstrut 3. A force required to flex strut 3 varies at the aforementionedangle.

Additionally, various modifications and embodiments of the endoscope tipassembly will be described.

[48]

Struts are provided outside the angle of view of an imaging deviceprovided in an endoscope tip portion. In particular, the struts areprovided outside the aforementioned angle of view, even when flexing onthe distal end side of the endoscope tip portion. In other words, thestruts are provided outside a truncated square pyramid region having topsurface positioned in cross-section at the proximal end of the base anda bottom surface positioned farther from the distal end of the base,even when the struts flex on the distal end side of the endoscope tipportion.

[49]

In a plurality of struts of the endoscope tip assembly, the length of astrut provided at a position corresponding to a corner of the angle ofview according to [48] is smaller than the length of a strut provided ata position corresponding to a side of the angle of view.

[50]

The endoscope tip assembly includes a plurality of struts, and thelength of a strut positioned at an angle within a predetermined range ina first direction in a plane parallel to the cross-section of the baseis smaller than the length of a strut positioned at an angle within apredetermined range in a second direction perpendicular to the firstdirection. For example, an endoscope tip assembly includes eight struts,the eight struts includes struts having a first length and struts havinga second length shorter than the first length, and the struts of thefirst length and the struts of the second length are alternatelyprovided. Alternatively, the endoscope tip assembly may include 16struts, the 16 struts includes struts having a first length and strutshaving a second length shorter than the first length, and four struts ofthe first length are projected on the first direction and the seconddirection and the remaining 12 struts are equally arranged between thestruts of the first length.

[51]

Each of the struts may be formed of a plurality of members. For example,a strut includes a core portion (inner portion) and a surface portion(outer edge portion) covering the core portion, and the surface portionis softer than the core portion. Alternatively, the strut may be formedof a material softer at the distal end than at the proximal endconnected with the base. For example, the strut has a distal end portionto which a tip member formed of a material softer than the material atthe proximal end portion is connected. The tip member is, for example, aspherical member or a tapered member having a shape tapered toward thetip. In addition, the tip member may be a member having a shape reducedin thickness toward the tip. The strut having the aforementionedstructure is less likely to damage the intestine when an endoscope tipportion is pulled out of the body.

[52]

The strut may be configured so that a force required to flex the strutis gradually reduced as the strut is flexed to the distal end side ofthe base. For example, the strut is configured to gradually increase thedepth of a notch provided in the outer surface (a surface positioned onthe same side of the outer surface of the base) of the strut, from theproximal end side to the distal side. Alternatively, the strut isconfigured to have a thickness gradually reduced from the proximal endside to the distal end side. In addition, the strut may be configured toreduce the force required to flex the strut after a force of apredetermined magnitude is applied.

[53]

The base may be provided with, in the outer surface, a groove portionextending from the proximal end side to the distal end side. The grooveportion has, for example, a width larger than the width of each strut,and accommodates at least a portion of the strut when the strut fallsdown on the distal end side of the base. The aforementioned groove ofthe base reduces resistance applied to the strut flexing on the distalend side. The depth of the groove portion is adjusted so that, forexample, of an outer layer (e.g., formed of a thermoset) and an innerlayer (e.g., formed of an elastomer) which constitute the base, only theouter layer has the groove portion.

[54]

The length L_(s) of a strut (the length from the proximal side of thebase to the tip of the strut) is shorter than the length L_(b) from theproximal side to the distal end side of the base. In other words, evenwhen the struts completely fall down on the distal end side, the strutsdo not extend further distally from the distal end side of the base, andthe struts do not appear in a captured image.

[55]

A base has a cylindrical shape with two-layers of an outer layer and aninner layer, and the inner layer may be provided with a projectionportion (crush rib). The projection portion protrudes, for example, in adirection in which the base is removed from an endoscope tip portion. Inother words, the projection portion protrudes on the distal end side ofthe base. The projection portion is, for example, an elastic memberformed of the same material as that of a strut. When the base isdisplaced in a direction in which the base slips off of the endoscopetip portion, friction force is generated between the projection portionand the strut, and the base is less likely to slip off of the endoscopetip portion. Further, the projection portion protrudes on the distal endside of the base, and the removal force upon drawing out the base fromthe endoscope tip portion is larger than the attachment force uponmounting the base to the endoscope tip portion.

[56]

A base has a cylindrical shape with two-layers of an outer layer and aninner layer, the outer layer may be formed of a first polymer, and theinner layer may be formed of a second polymer having a hardness smallerthan that of the first polymer. The first polymer includes, for example,a thermoset, and the second polymer includes, for example, an elastomer.Specifically, the first polymer includes polyetheretherketone (PEEK),polyphenylsulfone (PPSU), polysulfone (PSU), polyetherimide (PEI),polyoxymethylene (POM), or the like, and the second polymer includessilicone rubber, fluoro rubber, urethane rubber, acrylic rubber, nitrilerubber, natural rubber, or the like. These materials are, for example,materials (biocompatible materials) not causing any problem when placedin the human body enabling use for medical applications. Further, theouter layer and the inner layer are integrally formed, and theaforementioned materials meet the requirement that the first polymerneeds to be a high-temperature resistant material. Still further, theendoscope tip assembly is used by being sterilized, and theaforementioned materials meet the requirements that the first polymerand the second polymer need to be materials resistant to gamma radiationand EOG sterilization.

[57]

The inner layer of the base may be provided with a tacky adhesive. Theadhesive is, for example, in the form of a film. The adhesive may beprovided only on a portion of the proximal end side of the inner layerof the base or may be provided over the entire surface of the innerlayer of the base.

[58]

In order to prevent water from intruding between the inner layer of thebase and an endoscope insertion portion, a watertight portion, such aspacking or an O-ring may be provided between the inner layer and theendoscope insertion portion. The watertight portion is provided, forexample, at least at one end of the base. Alternatively, the watertightportion may be provided around a hole which is defined in the base topenetrate the outer layer and the inner layer.

The invention claimed is:
 1. An endoscope tip assembly comprising: aring-shaped base configured to be removably mounted to a distal end ofan endoscope insertion portion; and a plurality of struts collapsiblyradiating from the base, wherein each of the plurality of strutsincludes a base-mount at a proximal end of the strut, an angled portionat a distal end of the strut, and a recessed portion between thebase-mount and the angled portion, a portion of the recessed portion isadhered to an inner surface of the base, another portion of the recessedportion is not in contact with the base during insertion and is incontact with the base during withdrawal, and the endoscope insertionportion has a larger extraction force required for extraction from abody than an insertion force required for insertion into the body.